Inherited control of crystal surface reactivity

Kurganskaya, Inna; Lüttge, Andreas

doi:10.1016/j.apgeochem.2018.02.003

Cited by 37 publications

(19 citation statements)

References 50 publications

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“…Different regions in the sigmoidal function seem to be governed by different dissolution mechanisms depending on the mineral cohesive energy and

Δ G

. These mechanisms can be observed experimentally when vertical scanning interferometry and atomic force or scanning electron microscopy are used to follow the surface topography during dissolution . In a typical curve like the one portrayed in Figure c, three mechanisms with different dissolution rates can be distinguished: –Mechanism I.…”

Section: Introductionmentioning

confidence: 93%

“…The dissolution of a solid material is a complex process which is simultaneously affected by the solid surface topology (exposed surface, nature of the atomic bonds, presence of impurities, defects, etc.) [9,10,15,19,20] In a typical curve like the one portrayed in Figure 1c, three mechanisms with different dissolution rates can be distinguished: -Mechanism I. Indeed, the driving force of dissolution is controlled by the Gibbs free energy (ΔG), which is closely related to the ion activity in the solvent.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms and Dynamics of Mineral Dissolution: A New Kinetic Monte Carlo Model

Martin

Manzano

Dolado

2019

Advcd Theory and Sims

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Mineral dissolution is a fundamental process in geochemistry and materials science. It is controlled by the complex interplay of atomic level mechanisms like adatoms and terraces removal, pit opening, and spontaneous vacancy creation that can be gradually activated at different energies. Though the development of a comprehensive atomistic model is key to go deeper into the understanding of this phenomenon, existing models have failed to reproduce the abrupt dependence of the dissolution rate with the Gibbs free energy ( G). Herein, a new atomistic kinetic Monte Carlo (KMC) model is presented, which, invoking the microscopic reversibility of chemical reactions, captures the experimentally observed sigmoid dependence of the dissolution rate and provides new insights on the concomitant dissolution mechanisms. As a salient result, the model predicts the possible existence of unreported close-to-equilibrium dissolution modes where spontaneous vacancies creation and pit opening can occur before adatom and terrace removal.

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“…Different regions in the sigmoidal function seem to be governed by different dissolution mechanisms depending on the mineral cohesive energy and

Δ G

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Mechanisms and Dynamics of Mineral Dissolution: A New Kinetic Monte Carlo Model

Martin

Manzano

Dolado

2019

Advcd Theory and Sims

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“…According to the research of Fischer et al ., the dissolution activity of the layered crystal has the characteristics of layer‐to‐layer inheritance; thus the thickness of the crystal will affect its dissolution activity. Compared to the low‐reactive point, the high‐reactive point is more likely to disappear when transferred between layers 31 . This implies that the thickness of the crystal should be an important factor affecting the dissolution activity and crystals with more layers, i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Compared to the low-reactive point, the high-reactive point is more likely to disappear when transferred between layers. 31 This implies that the thickness of the crystal should be an important factor affecting the dissolution activity and crystals with more layers, i.e. crystals with greater thickness, will exhibit lower dissolution activity.…”

Section: Effect Of Morphology On Dissolution Ratementioning

confidence: 99%

Enhanced dissolution rate of magnesium hydroxide via magnesia/ammonium acetate hydration system: statistical optimization and possible mechanism

Tang

Chuang

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND The dissolubility of magnesium hydroxide is often the main factor limiting its application effect in the environmental field, and the dissolution rate of magnesium hydroxide during its synthesis is also worthy of attention. In this paper, response surface methodology was used to synthesize magnesium hydroxide with different dissolution rates through a magnesium oxide/ammonium acetate hydration system, and the possible formation mechanism as well as dissolution performance is discussed. RESULTS Compared with the hydration temperature and time, the concentration of ammonium acetate has a more significant effect on the dissolution rate of hydrated magnesium hydroxide. A maximum dissolution rate of 43.8 ± 0.3 mmol min−1 mol−1 magnesium hydroxide could be obtained when the working factors were ammonium acetate concentration 15 g L–1, hydration temperature 75.5 °C and time 112 min. CONCLUSION The correlation study between structural characterization and the dissolution test shows that the complexation and replacement of acetate, in situ generation and release of ammonia appear to have some critical effects on magnesium hydroxide crystallization behaviour and induce the formation of thin, curved and defective structures. Crystals with such structures have been reported to have a higher dissolution activity. The results of this study provide an indication for screening hydration synthetic agents of high‐dissolution‐rate magnesium hydroxide. © 2020 Society of Chemical Industry (SCI)

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“…In addition, little is known about the rates of dissolution along grain boundaries for different mineral systems, so that it cannot yet be determined whether the heterogeneous model or the homogeneous model is more realistic. Moreover, crystals often contain defects so that their reactivity may in fact be heterogeneous, which could affect both reaction rates and dissolution patterns (Fischer et al, 2018). Future work focusing on the development of more sophisticated models and the experimental measurement of dissolution rates along grain boundaries, may provide a way to resolve these issues.…”

Section: Discussionmentioning

confidence: 99%

Impact of grain size and rock composition on simulated rock weathering

Israeli¹,

Emmanuel²

2018

Earth Surf. Dynam.

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Abstract. Both chemical and mechanical processes act together to control the weathering rate of rocks. In rocks with micrometer size grains, enhanced dissolution at grain boundaries has been observed to cause the mechanical detachment of particles. However, it remains unclear how important this effect is in rocks with larger grains, and how the overall weathering rate is influenced by the proportion of high-and low-reactivity mineral phases. Here, we use a numerical model to assess the effect of grain size on chemical weathering and chemo-mechanical grain detachment. Our model shows that as grain size increases, the weathering rate initially decreases; however, beyond a critical size no significant decrease in the rate is observed. This transition occurs when the density of reactive boundaries is less than ∼ 20 % of the entire domain. In addition, we examined the weathering rates of rocks containing different proportions of high-and low-reactivity minerals. We found that as the proportion of low-reactivity minerals increases, the weathering rate decreases nonlinearly. These simulations indicate that for all compositions, grain detachment contributes more than 36 % to the overall weathering rate, with a maximum of ∼ 50 % when high-and low-reactivity minerals are equally abundant in the rock. This occurs because selective dissolution of the high-reactivity minerals creates large clusters of low-reactivity minerals, which then become detached. Our results demonstrate that the balance between chemical and mechanical processes can create complex and nonlinear relationships between the weathering rate and lithology.

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Inherited control of crystal surface reactivity

Cited by 37 publications

References 50 publications

Mechanisms and Dynamics of Mineral Dissolution: A New Kinetic Monte Carlo Model

Mechanisms and Dynamics of Mineral Dissolution: A New Kinetic Monte Carlo Model

Enhanced dissolution rate of magnesium hydroxide via magnesia/ammonium acetate hydration system: statistical optimization and possible mechanism

Impact of grain size and rock composition on simulated rock weathering

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